1. Field of the Invention
The present invention relates to a cross-section processing and observation apparatus for performing cross-section processing and observation of a sample.
2. Description of the Related Art
As a method of analyzing internal structure and defects in a semiconductor device or the like, there is known a cross-section processing and observation method, in which a focused ion beam is used for cross-section processing of a sample to expose a cross-section including a desired structure or a defect and a scanning electron microscope is used to observe the cross-section. According to this method, a desired observation target inside the sample can be exposed with pinpoint accuracy, and hence the structure or the defect can be observed quickly.
A method of performing cross-section processing and cross-section observation by a focused ion beam is also disclosed (see JP-A-2011-54497). According to this method, cross-section processing and observation can be performed even by an apparatus not including a scanning electron microscope.
In recent years, there has been known a technology of combining a plurality of cross-sectional observation images acquired by cross-section processing and observation to construct a three-dimensional image of a region subjected to etching by cross-section processing. In order to construct a high density three-dimensional image, several tens to several hundreds of observation images are acquired and combined to construct a three-dimensional image. Therefore, an apparatus that automatically performs a process of cross-section processing and observation has been necessary.
In the case of automatically performing the process of cross-section processing and observation, the process needs to be finished when a desired observation target is exposed in a cross-section. As a method of monitoring the end point of the process, for example, there is known a method of recognizing an acquired observation image and finishing the process when a desired observation target has appeared in the observation image.
However, in the case of a sample in which a device pattern appears in the cross-section such as a semiconductor device, the shape of the device pattern changes in every observation image, and hence a change in the shape of the device pattern may be recognized by mistake as the appearance of an observation target. Thus, it has been difficult to monitor the process end point.